5,033 research outputs found
Slow epidemic extinction in populations with heterogeneous infection rates
We explore how heterogeneity in the intensity of interactions between people
affects epidemic spreading. For that, we study the
susceptible-infected-susceptible model on a complex network, where a link
connecting individuals and is endowed with an infection rate
proportional to the intensity of their contact
, with a distribution taken from face-to-face experiments
analyzed in Cattuto (PLoS ONE 5, e11596, 2010). We find an extremely
slow decay of the fraction of infected individuals, for a wide range of the
control parameter . Using a distribution of width we identify two
large regions in the space with anomalous behaviors, which are
reminiscent of rare region effects (Griffiths phases) found in models with
quenched disorder. We show that the slow approach to extinction is caused by
isolated small groups of highly interacting individuals, which keep epidemic
alive for very long times. A mean-field approximation and a percolation
approach capture with very good accuracy the absorbing-active transition line
for weak (small ) and strong (large ) disorder, respectively
Effect of degree correlations above the first shell on the percolation transition
The use of degree-degree correlations to model realistic networks which are
characterized by their Pearson's coefficient, has become widespread. However
the effect on how different correlation algorithms produce different results on
processes on top of them, has not yet been discussed. In this letter, using
different correlation algorithms to generate assortative networks, we show that
for very assortative networks the behavior of the main observables in
percolation processes depends on the algorithm used to build the network. The
different alghoritms used here introduce different inner structures that are
missed in Pearson's coefficient. We explain the different behaviors through a
generalization of Pearson's coefficient that allows to study the correlations
at chemical distances l from a root node. We apply our findings to real
networks.Comment: In press EP
When orofacial pain needs a heart repair
Objectives: The association of chronic orofacial pain (COFP) and congenital heart disease has never previously been reported. We report the first case of COFP secondary to a right-to-left shunt (RLS) due to asymptomatic patent foramen ovale (PFO) in a patient with prothrombotic states. Materials and methods: A 48-year-old female patient presented with a 10-month history of left-sided facial pain who was initially diagnosed with persistent idiopathic facial pain (PIFP) on account of its similar characteristics. Magnetic resonance imaging (MRI) of the brain revealed gliosis and carotid siphon tortuosity; in addition, hyperhomocysteinaemia due to the homozygosis mutation for 5,10 MethyleneTetraHydroFolate Reductase was identified. Transcranial doppler ultrasonography was requested from a neurology consultant which revealed a high degree of RLS. Subsequently, a cardiological evaluation was performed; the specialist requested a transesophageal echocardiography that detected an interatrial septum aneurysm with PFO. Results: Based on the analysis of the patient's high degree of RLS, prothrombotic state and gliosis in relation to age, the cardiological consultant chose to perform a percutaneous closure of the PFO to avoid the risk of a cryptogenic stroke. After PFO closure, a complete remission of the pain was obtained. Conclusions: The disappearance of the pain supports the possible association between RLS and COFP. PFO with RLS has been suggested as a risk factor for cryptogenic stroke, especially in association with other thromboembolic risk factors. Therefore, the early detection, in this case, could be considered a possible lifesaver. Communication between different care providers is essential when the patient presents symptoms of facial pain which are of an atypical nature
Towards Chatbot-Supported Self-Reporting for Increased Reliability and Richness of Ground Truth for Automatic Pain Recognition: Reflections on Long-Distance Runners and People with Chronic Pain
Numerical Study of the Optical Response of ITO-In2O3 Core-Shell Nanocrystals for Multispectral Electromagnetic Shielding
Nowadays materials to protect equipment from unwanted multispectral electromagnetic waves are needed in a broad range of applications including electronics, medical, military and aerospace. However, the shielding materials currently in use are bulky and work effectively only in a limited frequency range. Therefore, nanostructured materials are under investigation by the relevant scientific community. In this framework, the design of multispectral shielding nanomaterials must be supplemented with proper numerical models that allow dealing with non-linearities and being effective in predicting their absorption spectra. In this study, the electromagnetic response of metal-oxide nanocrystals with multispectral electromagnetic shielding capability has been investigated. A numerical framework was developed to predict energy bands and electron density profiles of a core-shell nanocrystal and to evaluate its optical response at different wavelengths. To this aim, a finite element method software is used to solve a non-linear Poisson's equation. The numerical simulations allowed to model the optical response of ITO-In2O3 core-shell nanocrystals and can be effectively applied to different nanotopologies to support an enhanced design of nanomaterials with multispectral shielding capabilities
Sparse Exploratory Factor Analysis
Sparse principal component analysis is a very active research area in the last decade. It produces component loadings with many zero entries which facilitates their interpretation and helps avoid redundant variables. The classic factor analysis is another popular dimension reduction technique which shares similar interpretation problems and could greatly benefit from sparse solutions. Unfortunately, there are very few works considering sparse versions of the classic factor analysis. Our goal is to contribute further in this direction. We revisit the most popular procedures for exploratory factor analysis, maximum likelihood and least squares. Sparse factor loadings are obtained for them by, first, adopting a special reparameterization and, second, by introducing additional [Formula: see text]-norm penalties into the standard factor analysis problems. As a result, we propose sparse versions of the major factor analysis procedures. We illustrate the developed algorithms on well-known psychometric problems. Our sparse solutions are critically compared to ones obtained by other existing methods
Cytotoxic activity of gemcitabine, alone or in combination with mitotane, in adrenocortical carcinoma cell lines.
Comparing comparators: A look at control arms in kidney cancer studies over the years
In the past decade, an increasing number of frequently positive randomised clinical trials have been completed, allowing new consideration of the present therapeutic armamentarium for advanced renal cell carcinoma. These studies were predominantly designed to compare the experimental drugs with 1 of 2 active control arms: interferon alpha-2a or sorafenib. Different from expectations, the final results of some of these studies were not in line with the predictions, and the reasons have not been fully investigated. Consequently, there is a great need for careful analysis of the studies carried out so far, chiefly the role and validity of the control arms. In this regard, the examination of patient baseline characteristics and other factors of potential interest seems fundamental for a correct analysis of the results of these trials and consequent optimal use of the available targeted agents
Piecewise smooth systems near a co-dimension 2 discontinuity manifold: can one say what should happen?
We consider a piecewise smooth system in the neighborhood of a co-dimension 2
discontinuity manifold . Within the class of Filippov solutions, if
is attractive, one should expect solution trajectories to slide on
. It is well known, however, that the classical Filippov
convexification methodology is ambiguous on . The situation is further
complicated by the possibility that, regardless of how sliding on is
taking place, during sliding motion a trajectory encounters so-called generic
first order exit points, where ceases to be attractive.
In this work, we attempt to understand what behavior one should expect of a
solution trajectory near when is attractive, what to expect
when ceases to be attractive (at least, at generic exit points), and
finally we also contrast and compare the behavior of some regularizations
proposed in the literature.
Through analysis and experiments we will confirm some known facts, and
provide some important insight: (i) when is attractive, a solution
trajectory indeed does remain near , viz. sliding on is an
appropriate idealization (of course, in general, one cannot predict which
sliding vector field should be selected); (ii) when loses attractivity
(at first order exit conditions), a typical solution trajectory leaves a
neighborhood of ; (iii) there is no obvious way to regularize the
system so that the regularized trajectory will remain near as long as
is attractive, and so that it will be leaving (a neighborhood of)
when looses attractivity.
We reach the above conclusions by considering exclusively the given piecewise
smooth system, without superimposing any assumption on what kind of dynamics
near (or sliding motion on ) should have been taking place.Comment: 19 figure
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